<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>自动消失消息提示</title>
<style>
    /* 样式可以根据需求自行定义 */
    .message {
        position: fixed;
        top: 20px;
        left: 50%;
        transform: translateX(-50%);
        padding: 10px 20px;
        background-color: #4CAF50;
        color: white;
        border-radius: 5px;
        box-shadow: 0 0 10px rgba(0,0,0,0.2);
        display: none;
    }
</style>
</head>
<body>

<div class="message" id="messageBox"></div>
<button onclick="showMessage()">显示消息</button>

<script src="https://code.jquery.com/jquery-3.6.0.min.js"></script>
<script>
function showMessage() {
    var messageBox = $('#messageBox');
    messageBox.text('这是一条自动消失的消息！');
    messageBox.fadeIn();
    setTimeout(function() {
        messageBox.fadeOut();
    }, 3000); // 3秒后自动消失
}
</script>

</body>
</html>